Merge branch 'release/4.0.0'

.travis.yml

README.md

composer.json

docs/01-introduction.md

docs/02-installation.md

docs/03-overview.md

docs/04-helpers.md

docs/05-strategies.md

docs/06-formatters.md

docs/07-types.md

docs/08-doctrine.md

docs/09-api.md

docs/README.md

phpunit.xml.dist

src/AbstractIP.php

src/Doctrine/AbstractType.php

src/Doctrine/IPv4Type.php

src/Doctrine/IPv6Type.php

src/Doctrine/MultiType.php

src/Exception/Formatter/FormatException.php